Mechanism for contact printing



Sept. 24, 1946. G. L. HASSLER MECHANISM FOR CONTACT PRINTING 2Sheets-Sheet 1 Filed Jan. 4, 1944 \NVENTOR Gerald Z. Haas/Er BY 3 i RNQW ATTORNEY 1 2 1946- G. 1.. HASSLER 2,408,310

MECHANISM FOR CONTACT PRINTING Filed Jan. 4, 1944 2 Sheets-Sheet 2lNVENTOR (Fern id [.flaasZer BY 1) M -Cr- M;

ATTO R N EY Patented Sept. 24, 1946 UNITED STATES PATENT OFFICEMECHANISM FOR CONTACT PRINTING Application January 4, 1944, Serial No.516,910

This invention relates to a mechanism for maintaining contact andregistry between an original and sensitized printing material duringcontact printing. More specifically, the invention has to do withmaintaining such contact and registry by extracting air from between theoriginal and printing material so that atmospheric pressure may bebrought to bear in maintaining them in intimate contact and inpreventing distortion of or relative movement between the two while theyare exposed to a source of light.

In printing from an original, as in photographic and in similar work,pressure has been applied externally for the same general purpose and avacuum has been employed by connecting a vacuum line to a printingframe, the latter system being used for holding both the original andprinting material flat against a surface within 6 Claims. (01. 95-73)the printing frame. No one of the systems heretofore used makes itpossible to assure registry and satisfactory contact between thematerial and the original being printed by a vacuum and while they arebeing advanced, for example, during printing from movie negatives orpositives.

In overcoming certain outstanding difiiculties in this art, themechanism herein described makes it possible to apply vacuum to printingmaterial and the original which is to be printed as they are movingeither continuously or intermittently. It is also one of the objects ofthis invention to maintain registry and contact between the materials byapplying vacuum at the edge of the material, and therefore, moreeffectively withdrawing the air from between the elements in contactwithout subjecting them to unnecessary pressure and while allowing themto remain at rest or to advance in perfectly flattened condition.

In printing from movie negatives or when working from positives of thattype, the material is rapidly advanced and yet is maintained in perfectcontact and registry so that the printed film will be more nearly anexact duplication of the original than would otherwise be possible. Thepresent system and the mechanisms here disclosed do not depend at all onthe structural strength or rigidity of the film or printing material andare not subjected to harsh treatment such as would tend to destroy theirsurface structure or otherwise damage them rendering them lesssatisfactory for subsequent printing or projection.

According to the invention, plates or sheet films or other originals areprinted by introducing them in superimposed relationship between acontacting pair of belts, these belts being wider than the original orprinting material and passing over rollers or other guiding means. Atleast one of these belts is to be suitably transparent so that light maybe passed therethrough for illuminating the original and light-sensitivematerial. At that part of the cycle within which the material issubjected to the printing light, a vacuum is applied to the spacebetween the belts by connections through hollow blades, one at eitherside of the mechanism. The simplest form of the invention would involveonly that mechanism just described in a general way, however, it ispreferable that an additional seal for the vacuum, that is, a sealcapable of excluding the outside atmospheric pressure from enteringbetween the belt structures, be provided. To that end, bands or stripsof relatively flexible material may be guided in such a manner as toform an additional covering at the edges of the belts above mentioned.It is also contemplated that other strip material or bands may be usedto reinforce and support the edges of the belts as they pass over theblades; these are also of superior friction characteristics.

For printing continuous strips such as movie films and the like, arotary mechanism is preferably used and the light-sensitive material andoriginal are introduced at one point along the circumference of thisrotary mechanism, and in their travel, are subjected to light rays forexposing the light-sensitive material. The film or original andlight-sensitive material are maintained in registry and in contact asthey pass through the exposure zone in this printer by extracting airfrom between them, said air being extracted at the edges which aresealed against atmospheric pressure by a system of bands or strips therebeing different modifications of this sealing means all of which will bedescribed in detail as the disclosure progresses. A vacuum is providedat the edges of the original and light-sensitive material by suitablycoring out portions of the rotating printing mechanism and connectingthe same through to a source of vacuum. Connections such as glands areused and make it possible to maintain the vacuum even though the printeris rotating and the source of vacuum to which it is connected isrelatively stationary.

It is to be understood that the invention applies to printing all typesof light-sensitive material such as photographic films, either negativesor positives, and to printing tracings or other printed matter onlight-sensitive material such as blueprint paper or those papers treatedwith diazotype dyes. The material to be printed may be of any size and,of course, the mechanism for the purpose is to be built in appropriatedimensions for that class of work for which it is intended. Throughoutthe disclosure and claims, when reference is made to an original and toprinting material or light-sensitive material, it is to be understoodthat the disclosure and scope of the invention are not limited to anyparticular material of thi sort, but include all materials used inprocesses wherein an image from an original is to be printed.

Having now generally described the invention and that field in the artof reproduction to which it applies, preferred embodiments thereof willbe described in detail by reference. to the attached figures of drawingsin which:

Fig. l is an elevation showing somewhat diagrammatically a simple formof the invention.

Fig. 2 is a sectional view taken at one end of Fig. l and showingdetails of the various belts,

and the manner in which an original and the sensitized material areretained and advanced by those belts.

Fig. 3 is a transverse section through Fig. 1 showing the constructionof the various belts and strips and the manner in which air is extractedthrough the vacuum blades.

Fig. 4 is a transverse section through a rotary printer to which theinvention has been applied.

Fig. 5 is a diagrammatic View illustrating the path of travel of theoriginal and the lightsensitive material through the printer of Fig. 4.

Fig. 6 is a sectional view showing in detail a modified form of theinvention as applied to a circular printer.

Figs. 7 and 8 are an. elevation and section, respectively, showinganother modification as applied to the circular type printer and inwhich a seal at the edges of the film and printing material is liftedfor entrance into and withdrawal from the printer of the feedingmaterial.

Fig. 9 is an enlarged detail View of a means for covering or sealing theopenings through which the teeth project.

Now referring to Fig, 1, a pair of belts indicated at It and II arespecifically to be referred to as clamping belts. These are passed aboutthe rollers I2, I3, I 3, and I5 for belt ID, and rollers I6 and I! forthe lower belt II. Each of these is impervious and considerably widerthan the widest material to be clamped or held thereby, and it isessential that at least one of the belts, that facing lights I8 and I9,be suitably transparent so that the rays from those lights may passthrough the belt and through the original to act on the sensitizedsurface of the printing material;

A table or platform 28 at the front of the machine serves to locate orplace each strip or sheet of printing material 2| and the original 22which may be a photographic plate, sheet film, tracing or any othermaterial adapted to be reproduced by any one of the known light-printingprocesses.

These elements are shown to a slightly larger scale in Fig. 2, and inthat figure, a sheet of film and printing paper have been inserted andare clamped between the adjacent faces of the upper belt Ill and thelower belt II. Of course, the lower belt need not be transparent and maybe of any material suitable for the purpose. These belts, especiallythat through which light is passed, should be of material not easilydamaged or scratched and in which thereare no inherent blemishes whichmight be printed through and recorded upon the sensitized material.

The rollers, especially rollers I2, I 3, I6, and I1, are preferablysimilar to wringer rollers and have steel centers with soft rubberbonded thereto. The rubber will allow a certain amount of pressure to beinserted between the pairs of rollers I2I6 and ItII so as to effect aseal against entry of atmospheric pressure, but will allow insertion ofthe original and material to be printed since the rubber may bedeflected for that purpose. It is to be understood that adjustments areto be provided, although not shown, for the purpose of maintaining thevarious belts tensioned and also for determining the proper amount ofpressure between pairs of rollers !2-I 6 and I3Il.'

Extending between the pairs of rollers at the opposite ends of the.belts i5 and II are the tubes 23 and 2A, one at either side, andprojecting inwardly to engage between the belts It and II are the blades25 and 2'6. These blades are soldered or welded or otherwise formed as apermanently connected part of the tubes, extending from a slitlengthwise in those tubes. The external surfaces of the blades arehighly polished and offer little resistance to the passing of the beltsor tapes along their length. The ends of the blades are tapered toassist in smooth action and improve the vacuum seal.

Friction strips 27 and 28, relatively thin and of a material more suitedto stand the Wear or" continued sliding along the blades may be used.They also improve the air seal between the surface of the blades and thesealing belts. The strips are guided by pulleys which are preferablyflanged so as to maintain the strips in proper alignment with the edgesof the clamping belts. Of course, there are a pair of strips 2'] and 28at each side of the machine.

If desired, special sealing strips may be employed, these beingrelatively soft and impervious strips guided by suitable pulleys in amanner similar to the friction strips just described, these sealingstrips being guided along the outer edges of the clamping belts therebyto increase the tendency of the moving belt and strip mechanism toresist entry of atmospheric pressure.

While it has not been illustrated, a support may be provided beneath thetravelling belt II so as to prevent any sagging of that belt, althoughit is not likely that such a support would be needed except in largermachines adapted to handle relatively heavy materials and in which thebelts themselves would be of considerable weight.

Each of the tubes 23 and 24 is connected through a line 29 to somesuitable vacuum system such as a shop Vacuum line or to a pump expresslyprovided for the purpose. One pair of the rollers, for example, rollersI2 and I6, is to be driven from a suitable source of power. It isnecessary to drive only one of these rollers, the other being geared tothat one. Of course, the strips need not be driven independently sincethey will be carried along with the clamping belts, the friction betweenthe strips andthe belts being considerably greater than the frictionbetween the strips and the polished blades.

In operation, light-sensitive material and an original are fed into thmachine :by superimposing the original properly over the light-sensitivematerial on the table 25 and then manually sliding them along until theyare engagedby the belts I 0 and I I'whereupon they willibe drawn intoair from between the clamping belts and will also withdraw any entrappedair between the original and light-sensitive material. The atmosphericpressure outside the clamping belts causes them to be tightly compressedand will also flatten and press the original and light-sensitivematerial into perfectly contacting and permanently registeringrelationship. The exposure to the source of light takes place while thematerials are flat, while they are in complete surface contact, and theeffect of the atmospheric pressure on the belts, and, incidentally,through to the materials being printed and from which the image isprinted, prevents any relative motion between them such as might causethe printing of a distorted image or one not as clear and precise in itsdetail as that on the original.

As the printing material and originals are discharged at the oppositeside of the device, the printing material may be developed out in anyone of the known ways, the developing and fixing or other subsequenttreatment of the sensi tive material depending upon that class ofmaterials employed and the various processes applicable thereto.

Now referring to Figs. i and 5, a rotary-type printer will be described,this printer being adapt ed to handle movie films or any other type ofprinting material which may be fed in long strips and, therefore, moreor less continuously. The printer consists of two discs or Wheels 36 and3!. These wheels are separately mounted and are rotatable on a commonaxis. While the wheels may be rotated by power applied thereto, it ispreferable that they be driven by the film itself, which will beadvanced by some other means of power (not shown). It is to beunderstood that where movie film is to be treated, the wheels will beprovided with teeth although such teeth have not been shown in thesefigures due to the relatively small scale and for purposes ofsimplifying the illustration. Such teeth are common in the art, and itis well understood that they engage series of openings or perforationsat the edges of films of this type.

In the diagrammatic view of Fig. 5, an original 32 is being fed into theprinter, and since the source of light is at the center, the sensitizedmaterial to be printed and indicated by numeral 33 is at the outer sideof the original. Series of rollers or pulleys 3! guide bands or strips35 and 36 which are for the purpose of sealing the edge of the materialand other points against entry of atmospheric pressure. These bands orstrips are of flexible, relatively soft and impervious material and arecarried around by their frictional contact with the outer rims of thewheels 36 and 3|.

These outer rims are separate from the main parts of the printer discsor wheels, and are so constructed mainly for purposes of design and easeof manufacture so as to form two annular chambers 31 and 58 which willbe closed by the tightly fitting rims 39 and 4H. These chambers areconnected by a plurality of radial openings such as 4| to other annularcored spaces 42 and 43. Each of these latter cored openings communicateswith a. vacuum line through glands 44 at one side and 45 at the other,said glands serving to connect the moving printer mechanism through tosome sort of stationary vacuum line or pump. Tubes 46 and 4? run fromthe glands to the source of vacuum which need not be shown or describedin detail here.

Each of the rims 39 and 40 is similar, and it will be noted that porousmaterial such as hard felt has been packed in an annular space extendingaround the periphery of each rim. This felt 68 serves to allow the airbetween the original and printing material to be extracted, yet willprevent rapid leakage and destruction of the vacuum in the event a sealis broken at any point, that being something which happens between thepoint of entry of the material and its point of exit. That part of theprinter circumference through which the sealing tapes do not cover thefelt packing $3 is not of great extent, and there is not suflicientleakage there to lower the vacuum appreciably. However, pressure plates(not shown) may be app-lied throughout that are thereby to lessen theeffect of leakage.

A series of small radial holes 69 connects the chamber 38 with the spacein which the porous material is packed and then the relatively smallspace 59 leads through. to the film. This construction, as beforestated, is duplicated at the opposite side.

At the center of the structure a high pressure, mercury vapor lamp 5!serves to illuminate the original and printing material, this lamp beingsupported by connections externally of the wheel hubs and havingwater-cooling chambers 52 and 53. Of course, other lighting means may beemployed.

In operation, vacuum is maintained at a desirable pressure and the filmor other original and printing material is fed to the machine beingengaged by the sprocket teeth also by the sealing tapes or bands 35 andhe vacuum withdraws air from between the material and thereby causesboth the original and the printing material to be pressed together inperfect contact since atmospheric pressure within the printer andwithout are equalized. There is no tendency for the original or thelight-sensitive matcrial to move relatively, and therefore perfect registration makes it certain that the printed image will contain all thedetail and definition of the original and will not be distorted withrespect thereto.

In Fig. 6 a modification is shown in which the light-sensitive material5 3 is considerably wider than the original 55. Where that is true, itis not essential that sealing tapes be employed since the added width ofthe printing material allows it to cover the felt or other porousmaterial through which air is extracted and thereby to exclude theatmospheric pressure from without. The mechanism of Fig. 6 otherwisesimilar to that just described with respect to Figs. i and 5.

Now referring to Figs. '2 and 8. a modification of the rotary-typeprinter will be described in which the seal at the edges is not obtainedby driven strips or tapes such as tapes previously described. In thismodification sealing tapes are stretched about the rims of the printerwheels and are tightly drawn against each riin, enclosing the porous orpervious felt strips and engag ing the outer edges of the him or otherprinting material. At the points of entry and exit for the film, thesetapes are lifted or folded upwardly so as to allow those functions totake place,

The printing mechanism is generally the same as that of Fig. 4 exceptfor the strips or tapes 56 and 51 which are prefer Joly of some elasticmaterial such as rubber. They are tightly drawn about the rims of theprinter wheels and are held in place by tension rings 53 and 59. For thepurpose of lifting or folding these tapes upwardly and outwardly so asto insert or allow the film to be discharged, special devices areemployed, those being indicated at ti! and 6!. They are identical onlyoppositely disposed and ar so constructed they slowly raise and turn theedge of the tape upwardly and outwardly throughout an angle of about 90and thereafter force that tape back downwardly The projection 52 isshown raising tape 56 which, at about the center line, will be foldedback and standing at about 90 from the plane of the entering film orother printing material. The eiTect is that at the point of greatestdeflection for the tapes, there is provided an opening amply wide forthe printing material to be inserted or for it to be discharged. Theopposite projection of the tape lifter iii), that at 63, quickly turnsthe tape down into its original position.

It can be seen that in this modification the seal over the film and alsoover the porous material is continuous except for that short distance inwhich the lifting mechanism functions to fold the tapes outwardly, Forthat reason, it is not necessary to provide any special provision formaintaining vacuum over that arc through which none of the materialbeing treated is in contact with the printing machine.

While the sprocket teeth usually on printers or other mechanisms throughwhich movie film or other perforated material is advanced have not beenshown here, it is contemplated that such teeth are to be employed andFig. 9 illustrates the manner in which sealing tapes are constructed foraccommodating the teeth which normally project beyond the outer surfaceof the film or printing material.

These strips may be cast Or molded from flexible, preferably elasticmaterial, such as Saran, Lucite or rubber having sufficient thickness ofthe molded tooth receiving cups to withstand the applied vacuum. In Fig.9, one rim of the printer of Fig. 4 is shown to a larger scale, the rimhere being more completely depicted since one of the sprocket teeth 64is evident. Thes teeth are of standard size and shape for the film,

all as is known to those skilled in this art.

A sealing strip or tape 65 having spaced tooth receiving cups or socketsii-5 is to be used where there are sprocket teeth. As an alternateconstruction, and one which will be found easier and cheaper tomanufacture, the cups may be replaced by continuous channels.

The invention has been described by reference to' preferred embodimentsthereof which are r erely illustrative and are not to be interpreted aslimiting thereon. Other modifications and variations in details will beapparent to those skilled in the art, and it is obvious that there areother uses for this mechanism beyond those specifically mentioned here.The invention is defined in the appended claims.

I claim:

1. Mechanism for contact printing including in combination, a rotaryprinting device including wheels rotatable about a common axis, aprinting light, a rim for each said wheel adapted to guide an originaland sensitized printing material at its edges only during a continuousprinting operation, chambers within said wheels and connections to asource of vacuum, sealing strips, one for each rim, rotatable with theWheels and means including a plurality of rollers for guiding saidsealing strips, connecting passages from the vacuum chambers in saidwheels to the edges of the original and material to be printed,including radially disposed openings leading to an an- 8 nular space,said annular space being filled with porous material.

2. In a device for printing light-sensitive material, the combination ofa source of light, means for conveying an original and light-sensitivematerial in substantially continuous lengths past said source of light,said means comprising rotary members having flanges adapted to receiveand to guide the original and sensitive material at their edges only,means for sealing the edges of the original and sensitive materialincluding tapes one at either edge of the material cooperating with thesaid flanges, and means for extracting air from between the original andsensitive material including a vacuum line, means for operativelyconnecting said vacuum line to a duct Within said rotary members, achannel in the rotary members adjacent the edges of the original andsensitive material and connecting passages leading from the duct to thechannel.

3. In a device for printing light-sensitive material, a light source,rotary members having a common center of rotation and being spaced aparta predetermined distance depending upon the width of the material to beprinted, rims on said rotary members adapted to receive the material tobe printed including an original and light-sensitive material, sealingmeans including tapes, one at either edge of the material and guidingmeans to maintain said tapes in operative relation to the rotary memberrims and in contact with the printing material, said tapes beingprovided with means for moving them in a direction to allow entry of theoriginal and sensitive material and also for discharge of that materialafter exposure, a vacuum line leading to each rotary member, a duct insaid member and a gland operably associated with each duct, passagesleading from said duct outwardly to the rims of the rotary members andan annular space at each rim adjacent the edges of the material to beprinted, thereby to connect the vacuum through to the said material forextracting air from between the original and sensitive material toassure contact and registry during exposure.

4. Mechanism for contact printing including in combination a rotaryprinting device including members rotatable about a common axis, aprinting light, a rim for each said rotatable member adapted to guide anoriginal and sensitized printing material at its edges only during acontinuous printing operation, chambers withing at least one of saidmembers and connections to a source of vacuum, sealing strips, one foreach rim, rotatable with the members and means including a plurality ofrollers for guiding said sealing strips, connecting passages from saidvacuum chambers in the members to the edges of the original and materialto be printed including a space filled with porous material.

5. In a device for printing light sensitive material, the combination ofa light source, conveying means including flexible tapes for permittingthe simultaneous introduction to and for conveying a substantiallycontinuous series of originals and light sensitive material past thelight source for effecting exposure of the light sensitive material,said conveying means being effective, after exposure of the lightsensitive material, to discharge both that material and the originalfrom the device, means including the said flexible tapes for sealing thelateral edges of both original and light sensitive material as they passthe light source, said sealing means being effective to seal the saidoriginal and light sensitive material by contact at the lateral edgesonly thereof, and means for extracting air from between the original andlight sensitive material including a chamber at each side of the deviceand conduits leading therefrom to a vacuum source, the said chambersextending in the direction of travel of the original and light sensitivematerial and being closely adjacent thereto, and said tapes overlappingboth the original and light sensitive material and the chambers.

6. In a device for printing light sensitive material, the combination ofa source of light, means for conveying an original and light sensitivemaable members having surfaces for receiving and guiding th original andlight sensitive material at their edges only, means for sealing theedges of the original and sensitive material, including tapes one ateither edge of the material cooperating with the said guiding surface,and means for extracting air from between the original and sensitivematerial including a vacuum line, a duct and means for operativelyconnecting said vacuum line to said duct, a channel adjacent the movablemembers and the edges of the original and sensitive material, said tapesoverlapping both the channel and the sensitive material, and aconnecting passage leading from the duct to terial in substantiallycontinuous lengths past 15 t e ch nelsaid source of light, said meanscomprising mov- GERALD L. HASSLER.

